Founder and CEO David Karp spoke at the DLD conference in Munich this morning, where he reiterated some of the company's recent milestones:

100+ million uniques per month

15+ billion pageviews per month

Tumblr, which is basically halfway between a blogging platform and Twitter, allows users to post photos, videos, and text. Critically, it also allows users to "follow" each other and "re-blog" the posts of others.

The latter concepts, which Twitter has also capitalized on with amazing success (through "following" and "re-tweets"), inserts reblogged posts into each user's timeline stream. Thus, anyone who "follows" a user, also sees the re-blogged posts.

This turns Tumblr users into editors and curators in addition to content creators. The sharing functionality allows posts to spread rapidly, just as links and headlines do on Facebook and Twitter. In Tumblr's case, though, the whole post is shared, not just the headline and link.

It's worth noting that this whole concept makes a mockery of the idea of traditional content "theft." If someone "re-blogged" a traditional newspaper story, inserting it into their own site, the newspaper would probably scream bloody murder and sic lawyers on them. And yet, on Tumblr, those whose posts are "re-blogged" feel nothing but gratitude and pride (thanks for sharing my work!).